Method and apparatus for conditioning and supplying clay to pottery forming machinery



May 2, 1950 w. J. MILLER 2,506,377

METHOD AND APPARATUS FOR CONDITIONING AND SUPPLYING CLAY T0 POTTERY FORMING MACHINERY 4 Sheets-Sheet 2 May 2, 1950 w. J. MILLER METHOD AND APPARATUS FOR CONDITIONING AND SUPPLYI CLAY To PoTTERY FORMING MACHINERY Filed'June 8, 1944 May 2, 1950 W. J. MILLER METHOD AND APPARATUS FOR CONDITIONING AND SUPPLYING CLAY TO POTTERY FORMING MACHINERY Filed June 8, 1944 4 Sheets-Sheet I5 INVENTOR May 2, 1950 2,506,377

w. J. MILLER METHOD AND APPARATUS FCR CONDITIONING AND suPPLYINC CLAY To POTTERY FCRMINC MACHINERY 4 Sheets-Sheet 4 Filed June 8, 1944 lll/MMIII.

Patented M., 2, 195o METHOD AND APPARATUS FOB CONDITION- ING AND SUPPLYING CLAY TO POTTERY FORMING MACHINERY william J. Miner, sammle, ra., mmm u Minn-i Pottery Engineerlng Company, Swissvale, Pa.. a corporation of Pennsylvania Application June 8, 1944, Serial No. 539,258

13 Claims. (Cl. 25-1) This invention relates to methods and apparatus for conditioning and supplying clay to pottery ware forming machinery. It has to do particularly with a new system of handling clay 2 ing machine. When the supply of clay falls below the demands, clay of a different texture and workability is supplied. production is necessarily curtailed with consequent increase in the cost of between a source of supply, for instance a filter 5 manufacture because of defective ware and idle press and the ultimate point of use, for example machine crews. Large chunks of clay placed in the clay feeding stations of an automatic jiggerthe pug mill could not be macerated into the ing machine to thereby reduce labor hours and very fine aggregates required for subdividing by expense and to provide the iiggering machine the puginto the tine textured clay required for with finer and more uniform texture clay and to l0 optimum jiggering and production of lump free reduce ware defects and rejects caused by lumps ware. A lump, hard or soft, less than Va", or in the clay thereby reducing the cost of the ware slurry seam, will result in scrapping of the piece and lastly to co-ordinate the supply of clay to the of ware. If the cakes were too hard generally pug mill with that required by the iiggering to produce pugged clay of optimum softness the machine. 16 adding of water in the pug was not practicable All lter cakes have hard brims, soft center because the mass remains only a fraction of a zones with the intermediate annular region havminute in the pug which is not sufllcient time to ing correct consistency for jiggering. Also all disintegrate large lumps and thereafter raise the filter cakes are harder in that zone which is made water content uniformly through the mass and at the top of the filter press and less hard at the the water will mix first with the soft clay. Should zone which is made at the bottom of the lter the pug mill become glutted from an oversupply press because the extruded water runs over the of clay, then the texture and workability of the region at the bottom from above during pressing. clay supplied is not the same as when the pug Adjacent cakes of a pressing differ in average supply is inadequate. A uniform supply of clay, hardness due to the age of the filter bags, the continuously delivered, that is to say not spascleanliness thereof or texture of weave. This is modic or with long intervals in between, insures inherent and cannot be avoided. Also, the reserve Clay 01' uniform texture plasticity and Wrkability stacks air dry at the periphery while awaiting providing it is not lumpy to start with. use. In the present invention, I propose to place the Heretofore, filter cakes have been removed truck directly under the press and drop the illter from the filter press and stacked in twin, vertical cakes in uniform progressive order directly on a columns on hand drawn trucks placed alongside truck as they are released from the filter press the press and then manually trucked to the pug vand to arrange the cakes in horizontally stacked mill and there manually wire cut into quarters relation with that portion of the filter cakes and chunks as large as can be conveniently which is formed at the top of the press and is i handled containing about 800 cu. in. thrown into the dryest portion of the cake, uppermost and the p ug mill by hand. There was no denite to do this by pulling the top of each cake outminute subdivision of the hard and soft zones of wardly in the press and permitting it to fall inthese large lumps prior to deposit in the pug nor clined into the desired arrangement. Truck loads subsequently within the pug to enable the pug of cakes are taken directly to a zone where they knives to denitely blend said small subdivisions are added to the trailing end of a procession of to thereby properly blend, homogenize, and plasfilter cakes which is being transported in endwise ticize the clay prior to discharge thereof from the fashion to a cutting oi point. The hard and soft pug barrel. 'I'he prior procedure involvedfthree zones of successive cakes in the procession are handlings of the material, one by the filter press arranged in overlapping relation relative to the operator, one by the truck puller and the third cutting plane. Preferably, the procession first by the pug operator. The feed into the pug was travels for a substantial period of time through a spasmodic and there was no controllable predetertreating zone wherein surface moisture is added mined volume delivery of clay into the pug mill to only to the harder brim zones and onto the top coordinate with the requirements of the jiggerbrim portion additionally spraying mist moisture,

s 7 the atmosphere in the treating zone being highly .humid and preferably hotter than the cakes to facilitate moisture deposit thereon through sweating, all subiect to regulations to establish and maintain prior to subdivision optimum water proportion of the mass as batches of cakes in the procession progress, and then subdividing and thereafter intermingling and deposit in the pug. At the cutting oif position. preferably relatively thin slices or wafers of clay are segregated from the procession by passing a cutting implement through a plurality of overlapping cakes, the cut preferably starting at the perimeter of the procession, said slice preferably folding or curling as itis detached, to further intermingle the hard brim portion with the softer portions of the slice. By slicing the material thin, large lumps in the pug supply are eliminated and the slice can be more completely and efficiently further subdivided and plasticized by the pug mill knives into minutely fine aggregates necessary for optimum fine texture jiggering clay and lump free ware. 'I'he slices are cut oil' periodically and deposited directly or indirectly in the pug mill. The volume delivery of clay into the pug is coordinated with the jiggering machines require. ments through automatic or manual control over the rate of feed of the procession of filter cakes to the cutting off point and the thickness of the slice by varying the periodicity of the stroke of the cutting implement and the shape of the curl by the rapidity of the stroke while cutting.

I thus substantially reduce pottery ware production cost by eliminating the pug feeding individual, reducing ware rejects chargeable to lumpy and off-consistency clay and insuring continuous production.

In the drawings:

Figure 1 is a side elevation of the preferred form of apparatus.

Figure 2 is a top plan view of the apparatus of Figure 1.

Figure 3 is a side elevation of a filter press showing a lift truck in loading position.

Figure 4 is an end view of the apparatus of Figure 1 taken in the direction of arrows I-l showing the loading end of the structure only.

Figure 5 is an enlarged detail in side elevation of the discharge end of the apparatus.

Figure 6 is an enlarged fragmentary detail of the sectional conveyor.

Figure 7 is a perspective view showing part of truck for transporting filter cakes between the filter presses and the loading end of the conveying means.

Figure 8 is a fragmentary detail partly in section showing a portion of the conveying means.

Figure 9 is an enlarged detaill of the segregating apparatus.

Figure 10 is a detail in section of a control valve.

Figure 11 is a side elevation illustrating modifications in the discharge end of the apparatus.

Figure 12 is an end view taken in the direction of arrows I2-I2 of Figure l1, of a reducer.

Figure 13 is a detail illustrating another form of cam for use with the cutting oif apparatus.

Figure 14 is a detail illustrating a filter cake.

Figure 15 is a detail illustrating how the travel of the filter cake conveyor may be automatically varied.

With reference to Figures l and 2, it is preferred to locate the conventional filter presses I and 2 adjacent the apparatus A for transporting the lter cakes to a segregating position B in man 4 order that the press operator may conveniently and in less time than ordinary, truck the output of the filter presses to the loading end C of the apparatus.

When a filter press is to be emptied, a wheeled lift truck 3, Figures 3 and '1. with the elevatable platform 4 inlowered position is maneuvered into position directly underneath press plates 5. As the filter cakes E are successively released by opening the bottom of the bags, they fall in brimwise fashion directly onto a support t, Figure 3. removably carried by the truck platform where they are arranged horizontally in inclined position against a thin section, rigid, divided backstop 1,-held in upright position by temporary props 8, Figure 3, until the truck is loaded. The upright wall of the backstop is inclined to the vertical at approximately the same angle as the main procession of filter cakes D, Figure l, to enable the group of filter cakes on the truck to be joined to the trailing end of the procession D at the proper angle in a manner to be described.

Support 6 is formed as a detachable load bearing portion of a conveyor composed of spaced, parallel roller chains 9 and I0, Figures 2 and 4 which in the loading zone C are carried by sprockets II mounted on stub shafts I2 supported by posts I3. The chain rollers of the top strands run on spaced parallel rails Il and I5 throughout this .zone. Each conveyor chain is formed with spaced upstanding tapered chain lugs I8, Figure '8, to thereby provide for an interfltting relation with the support 8 which is constructed of spaced pairs of rigid upper and lower slats I'I and I8, Figures 6 and 8, joined at the ends to marginal strips I9 of resilient or flexible material such as rubber or fabric by screws 20. The upper slats form a non-slip load receiving surface, and the underneath slats are tapered along the edge near the ends. to be received in the notches formed between chain lugs I6. Support 6 is preferably of a length to receive one press load of illter cakes when filled and is wider than the truck platform 4, see Figure 4. Y

To join a truck load of filter cakes to the trailing end of column D,`Figure 1, the truck is backed into the open end of the conveyor between posts I3 with the platform and support 6, raised to clear the chains 9 and I0. When the leading end of the trucked support 8 and the trailing end of the preceding conveyor borne support 2| abut, platform l is lowered. to thereby deposit support 6 on the conveyor chains in abutting relation with support 2| and the backstop 1 against the face of the last filter cake in column D. The backstop 1 is quickly removed by pulling the sections out laterally from under the front cakes which fall forwardly a short distance equal to the thickness of the backstop against the main column of cakes D, the weight of the material and its normally sticky, plastic condition causing the' entire mass to be more or less stuck tightly together.

At the encl4 of a short horizontal run in the loading zone C, the conveyor curves upwardly on rails Il and I5 through a sealing boot 22, Figure l, into an inclined humidifying chamber 23 supported by uprights 24.

Inside the chamber, the column D is exposed to the action of a highly humid atmosphere which is circulated by a blower 25 and exhausted into the lower end of the chamber through pipe 26 and stack 21, and sucked out of the upper end of the chamber and back to the blower 2S through stack 28 and pipe 29. Dampers 30 are provided to control circulation and humidiners in the form s h of valved pipes 3| having nozzles (not shown) inside the chamber are provided to spray water mist or steam thereinto under controlled pressure to thereby wet the tops of the filter cakes which are the hardest portions thereof as explained previously. Steam coils 3Ia are to heat their chamber when desired and are controlled by valve 3Ib in steam line 3|c. c

'I'he column of clay D emerges from the chamber at an upper level through a sealing boot 32, Figure 5, and the slatted support 8, may be received on a smooth surfaced drum 33 rotatable by sprocket shaft 34, which is rotatable in bearings 35, mounted on posts 33 ,secured to elevated pug platform31. The drum is larger in diameter than the drive sprockets 38, on shaft 34 to lift the slats out of the notches between chain lugs when the chain starts to curve around the sprockets to compensate for diierence in pitch.

diameter of chains I4 and I5 and support 8.- Where the straps I3 of supports 8 are formed of resilient material, the drum may be omitted because the rubber will stretch and allow the support 3 to travel around the sprockets with the chains. Said sprocket shaft 34 is driven by a motor 33', Figure 5, mounted on the platform, through a variable speed transmission 38 having a manual control 40 to regulate the speed of travel of the conveyor and hence the column to that required to supply the requirements of the forming machine through the pug mill 4|. If desired, an automatic control may be provided, for instance, by means of a pressure sensitive member 38a, Figure 15, arranged to reflect the clay pressures insidethe pug mill barrel 4|a at or near the delivery end thereof and transmit them to a member, for example a rack 39h which engages a pinion 38e on a control shaft 39d of variable speed transmission 38.

The leading end of the column D is received on a stationary inclined ramp 42, Figures 1 and 5 supported on posts 43 secured to -platform 31. It is caused to slide thereover and b e projected -outwardly therefrom by the upward thrust of the balance of the column of clay into a cutting oil position over or adjacent the hopper 44 of pug mill 4|. The natural adhesive bond between the filter press cakes enables the forward end of the column to be projected outwardly into an unsupported position beyond the end of the ramp without sagging or breaking oil, although it is preferred to cut through the column at or adjacent the upper end of the ramp to provide resistance to the cutting wire and control the path and manner of slice fall and position of deposit in the pug hopper.

The lead end of the column D is cut oif periodically by a slicing wire 45 suspended between the legs of a yoke 43, Figure 9, attached to the piston rod 41 of an air cylinder 48 adjustably secured to a platform 43 supported by posts 58, Figure 5. The actuation of the air cylinder is controlledby a pressure differential valve Figures 9 and 10, having an inlet connected by pipe 52 to a pressure equalizing tank 53 in which pressure is maintained by a compressor 54 driven by motor 55. On the outlet side of the valve is a pipe 58 leadin g to the lower end of the cylinder 48, with a regulating valve 55 therein. Another pipe 58, leads from valve 5I to the upper end of cylinder 4|, Figure 5, and has a regulating valve 58' therein. 51 is a vent pipe in valve 5|, Figures 5 and 10.

When cam 33, Figure 9, depresses pin 80, valve 58, Figure 10, permits the escape of air pressure in cavity 58a through hole 32 and vent 83 while cession.

58 with the tank 53 through duct 84 s. air leaking through vent 14 into chamber 58h pushes piston 3| to the left. 'I'his connects pipe and cut away portion 55 in the valve body to force the cutting wire downwardly .through the clay. Air ahead of the air cylinder piston is vented by backflow through pipe 58, notch 68 and vent-pipe 51.

Cam 88 is mounted on the drive shaft 88 oi a variable speed transmission 61, Figures 5 and 9. having a control 10 for adjusting the shaft speed. A motor 1I drives the transmission. It is preferred to cut through the clay quickly and therefore the pin 50 which unseats the ball valve is held in only for such length of time as required for the cutting wire to reach the bottom of its stroke under full tank pressure. The cam 68 is developed so as to release the pin as soon as this happens, and spring 12, Figure 10, forces the ball valve back in its seat whereupon air leaks through vent 13 into the chamber 58a forces vpiston 85 to the right due to the area differential occasioned by stem part 58a which is exposed to atmospheric pressure. This connects pressure tank 53 with pipe 58 through duct 15, pipe 58 being vented to atmosphere thereby raising the cutting wire rapidly. Should clay be cut from the advancing procession D on the return stroke it does not matter because the material will fall into the pug mill, and for that matter, the cam as illustrated at 83 in Figure I3, may be developed with two control surfaces 84 and 86 so as to cause the Wire to cut a full charge on each half stroke. f

It will be observed that the cutting wire moves vertically whereas the procession D is projected at an angle to the vertical. This causes the wire to cut across the column at an angle thereto thus producing a slice ofclay composed of material from a cross section of a plurality of filter cakes at various annular zones. It is preferred to form very thin slices of clay to thereby segregate hard and soft zones, see Figure 14, wherein |31 indicates the excess hard peripheral zone, |38 the excess soft central zone and |39 the intermediate,

optimum consistency zone, into its smallest practical portions prior to deposit in the pug to thereby predetermine the largest particle that can possibly be incorporated in the ware, thus facilitating and greatly reducing pugging requirements thereof. The periodicity of the cutting wire stroke and the speed of travel of procession D may be adjusted to obtain slices of clay of any desired thickness.

The pug mill 4| is of conventional construction having a hopper 44 for receiving the slices of clay cut oil.' from the procession D which is located in close proximity to the leading end of the prov Said pug mill is driven by a motor 16, Figure 2, transmission 11 which may be automatically controlled if desired in the manner previously described in connection with the structure of Figure 5. Connected to the pug mill outlet is a downwardly curved pipe 18 having its discharge outlet at a lower level than the pug mill directly over the clay feeding position of an automatic potteryware jiggering machine 8| resting on the :door therebelow at one side of platform 31, Figure 2. Slices of clay are automatically cut oil. from the extrusion through pipe 18 and deposited on successively presented molds 88 to be fabricated into ware.

In front of sprockets 38 or drum 35, Figure 5, is positioned a. curved guard 82 for guiding the supports 8 around the axis of shaft 34 and into the clearance space .between a downwardly inclined through an adjustable variable speed,

7 belt 89 and the chains 9 and I0. The purpose of belt 85, which runs between a roller 81 supported in bearings on posts 36, Figures 1 and 5, and a roller 88 on sprocket shaft 89 supported by posts 90 resting on the door is to support and control vthe rate of advance of the slatted supports 6, in

inverted position in engagement with the chains 9 and I0 whilst they are being returned to a lower level. The direction of travel of chains 9 and i is reversed as they travel around sprockets 9| on shaft 89 and a horizontal run is provided between sprockets 9i and sprockets 92 on posts 93, this being the unloading zone where the supports 9 are removed from the conveyor by trucks 9 which may be backed into the space between the chains as in the loading of clay into the conveyor, however with the platform 4 in lowered position to be raised to lift a slatted support 6 from the chains and carry the same back to the filter presses for refilling.

Instead of cutting off the lead end of procession D by means of a reciprocating cutting wire,

I may employ the pug mill knives 94, Figure 1l, to do so, by providing an opening in the side of the pug mill barrel adjacent the knives and connecting thereto a tapered rectangular section inlet nozzle 95. The pug mill in such event would be raised to the proper level so that the side opening would be in line with the procession. I prefer to reduce the diameter of the procession D and change the cross sectional shape thereof from round to rectangular and to do so have provided a reducer 99 which ls interposed between the ramp 42 and the nozzle 95 and rests on a frame 91 and projects upwardly at the same angle of inclinationas the procession D. Said' reducer comprises four roller supported belts 98, 99, |00 and l0! arranged on the frame work to form a rectangular passage, Figure 12, converging toward the nozzle 95 through which the lead end of the procession D travels, the lower belt 98 being driven by a chain I 02 driven by sprocket shaft 34 so that the movement of the belt will be coordinated with the speed of travel of the procession D. As the pug mill knives revolve, they will shave off slices of clay from the leading end of the procession to be pugged and extruded as aforesaid.

I claim:

l. The method of feeding a pug mill with clay which comprises, forming a column composed of plastic filter cakes with the side surfaces of the cakes in abutting relationship, moving the columnas a unit in endwise fashion towards an elevated cutting off position over the pug mill, slicing downwardly through the column at an angle to the longitudinal centerline thereof to produce a slice of clay composed of material from a plurality of cakes and to drop the slice by gravity into the pug mill.

2. In the manufacture of potteryware, the method of feeding a pug mill with clay which comprises, forming a procession of forwardly inclined overlapping lter cakes laid one against the other, moving the procession along an inclined plane to a cutting off position, 'slicing across the leading end of the procession in such fashion as to produce laminated bodies of clay, and from time to time adding to said procession additional filter cakes.

3. The method of feeding clay to a pug mill which comprises, forming a column composed of plastic filter cakes with the side surfaces of the cakes arranged in abutting relationship, moving the column as a unit in endwise fashion through a moisture modifying zone, to an elevated cutting oi position, slicing through the column at an angle to the longitudinal centerline thereof to produce a slice of clay composed of material from a plurality of cakes and dropping the slice by gravity into the pug mill.

4. The combination of a. pug mill with a support for carrying ilter press cakes from a. filter press to a segregating zone. conveying means for said support, segregating means for segregating material from said cakes in said zone and means for depositing filled supports directly on said conveying means' and for removing empty supports therefrom and carrying them away.

5. In combination with a pug mill, a support l for carrying filter press cakes to a segregating zone, means for segregating clay from said cakes in said zone, conveying means for transporting said supports to said zone and means for depositing filled supports on said conveying means and removing empty supports therefrom and carrying them away.

6. In combination with a pug mill, movable carrying means formed to support a. procession of filter press cakesvlaid one against the other, a. chamber through which the procession passes, means for supplying moisture to said chamber and segregating means arranged to detach material from the leading end of said procession to be deposited in said pug mill. l

7. In combination with a pug mill, a support for carrying filter press cakes in horizontally stacked relation to a segregating zone, means for segregating clay from said cakes in said zone, conveying means for transporting said supports to said zone arranged to move said supports along an inclined plane to project the filter cakes at an angle relative to the path of travel of the segregating means to enable the cutting off of laminated bodies of clay from the stack of filter cakes, and means for depositing filled supports on said conveying means and removing empty supports therefrom and carrying them away.

8. In combination with a pug mill having an inlet and movable macerating members, movable carrying means formed to support a procession of filter cakes laid one against the other, means for leading the forward end of the procession through the pug mill inlet to be cut oi by the macerating members and a reducer for changing the cross sectional size of the procession before entering the pug mill.

9. Apparatus for feeding clay to a pug mili comprising a support for carrying filter press cakes, conveying means for carrying said support to a cutting off position, clay segregating means at said position, means for moving said conveying means and means for depositing filled supports directly on said conveying means and for removing empty supports therefrom and carrying them away.

10. Apparatus for feeding clay to a pug mill comprising afmovable support formed for carrying a procession of lter cakes stacked on edge and laid one against the other to a cutting of! position, a chamber through which the support is carried, means for supplying moisture to said chamber and segregating means for detaching material from the leading end of the procession of lter cakes.

11. In the manufacture of potteryware, the method of feeding clay to a pug mill which comprises, forming a column of filter cakes arranged in overlapping relation and in forwardly inclined position relative to the vertical, moving the columns along anupwardly inclined plane, cutting across the leading end of the column in a vertical direction to detach a. laminated slice of clay composed of the material from several lter cakes and depositing the cut material in a pug mill.

12. Apparatus for supplying clay to a pug mill comprising, a conveyor having detachable filter press cake supports, and a section arranged in an inclined plane to project the end of a column oi' illter cakes over a pug mill, and a cutter at the upper end of the inclined section of the conveyor for cutting 01T clay and dropping the same into the pug mill.

13. Apparatus for supplying clay to a pug mill comprising. a conveyorhaving detachable lter press cake supports, and a section arranged in an inclined plane to project a column of cakes above the pug mill into a cutting oir position, means v for detaching bodies of lay from the column and means for loading illter'press cake supports onto the conveyor.

4WILLIAM J. MILLER.

10 REFERENCES crrlm The following references are of record in the tlle of this patent:

UNITED STATES PATENTS Number Name Date 49,396 Fulton Aug. 15, 1865 78,181 Brown May 26, 1868 295,298 smith Mar. 18, 1884 320,865 Frey June 23. 1885 399,025 Evans Mar. 5, 1889 418,962 Steele Jan. 7, 1890 964,512 Handle July 19, 19.10 1,657,172 Monroe Jan. 24, 1928 1,740,631 Stockmar Dec. 24, 1929 1,884,346 Stewart Oct. 25, 1932 2,180,757 Hermann Nov. 21, 1939 2 185,459 Hardgrove Jan. 2, 1940 2,277,248 Nardil Mar. 24, 1942 2,335,925 Emerson May 9, 1943 2.359.995 Korum Oct. 10, 1944 

